Enclosed housing for electrical switches



May 2, 1939. R. H. OLLEY 2,156,572

ENCLOSED HOUSING FOR ELECTRICAL SWITCHES Filed May 27, 1936 2Sheets-Sheet l a I Will [17m I INVENTOR. BY Bay ma a @115! ATTORNEYS May2, 1939. R. H. OLLEY ENCLOSED HOUSING FOR ELECTRICAL SWITCHES Filed May27, 1936 2 Sheets-Sheet 2 INVENTORY Jig 11101143. 0119 ATTORNEYS.

Patented May 2, 1939 UNITED STATES PATENT OFFICE ENCLOSED HOUSING FORELECTRICAL SWITCHES Application May 27,

9 Claims.

This invention, in general, relates to enclosed explosionproof housingsfor electrical apparatus such as switches, and the like.

The invention has as an object an enclosed housing having an open side,a cover detachably secured to the open side of the housing, meansoperable to lock the cover against removal and actuate the switch intoclosed position, said means being also operable to open the switch andunlock the cover from the housing while the switch is in open position.

The invention has as a further object a switch actuating mechanism andcover lock which is inoperable to close the switch while the cover isremoved from the housing.

The invention has as a further object an enclosed explosionproof housingof the type referred to of such structure as to prevent accidentalclosing of the switch while the cover is removed from the housing, thestructure being particularly economical and efficient in operation.

The invention consists in the novel features and in the combinations andconstructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanyingdrawings in which like characters designate corresponding parts in allthe views.

Figure 1 is a top plan view of the housing with the cover thereof and aportion of the switch therein removed.

Figure 2 is a sectional view taken on lines 2-2, Figure 1.

Figure 3 is a fragmentary top plan view of the housing with the cover inplace.

Figure 4 is a fragmentary, sectional view taken through the housing onlines 44, Figure 3.

Figure 5 is a top plan view of a receptacle and supporting plate, thesame being removed from the housing in Figure Figure 6 is a sectionalview taken on line B6, Figure 5.

Figure '7 is a top plan view of a modified form of housing with aportion of the cover being broken away.

Figure 8 is a cross sectional view of the housing and the apparatusmounted therein shown in Figure '7.

Figure 9 is a fragmentary, sectional view of the right hand portionshown in Figure 8 and with the cover removed from the housing.

Figure 10 is a perspective view of the switch contacts.

In Figures 1 to 6, I designates the housing,

1936, Serial No. 82,076

which, as here shown, is of circular contour, being open at the top andbeing provided with a detachable cover 2. The top opening of the housingI is threaded internally, as at 31, and the bottom portion of thebell-shaped cover 2 is provided with complemental threads. The cover 2is formed with a radially extending flange coacting with the marginaltop edge of the housing I about the opening thereof, as shown in Figure4. The housing here shown is adapted particularly to house a fusereceptacle.

The bottom wall of the housing is provided with an outwardly radiallyextending flange provided with a plurality of holes 32 by which thehousing is mounted upon the wall or other suitable support and withinthe housing, the bottom wall is formed with a pair of upwardly extendingbosses 38 on which is supported a disk 25 of suitable insulatingmaterial. The disk 25 is secured to the bosses 38 by means of screws 29.

A pair of resilient contact members it are secured at one end toterminals which in turn are secured to the insulating disk 25, as byscrews 21 The outer or free ends of the contact arm l6 are secured to aninsulating block [9 which extends a short distance beyond the peripheryof the disk 25. The outer ends of the arm 16 are also provided withcontacts I! which coact with stationary contacts 6, 1, carried by a diskI5 of insulating material superimposed upon and supported by the disk25. The contacts 6, l, are electrically connected to the center contactand the shell of the fuse receptacle.

Spacer posts l8 are inserted between the disks 25, I5, and are securedto the disk 25 by screws 3| and to the disk l5 by screws 28. The contactarm l6 and contacts 6, 'l are so arranged relatively that the contactsI! of the arm l6 normally engage the contacts 5, 1. The wires of thecircuit controlled by the fuse 40 mounted in the shell M are connectedto the terminals 20 by the screws 24. In addition to the resiliency ofthe arm "5, a helical compression spring 3 may be arranged beneath theblock Hi to elevate the terminals I1 into engagement with the contacts6, I.

In order to prevent removal of the cover 2 while the fuse circuit isalive, means is provided for disengaging the contact H from the contacts6, 1, previous to the removal of the cover 2 from the housing.

As here shown, this means comprises a screw 5 threaded through avertically extending aperture in the side wall of the housing and beingarranged to engage the flange of the cover 2. The flange of the cover 2is provided with an opening 33 arranged to receive the upper end of thescrew 5, when the cover is screwed into place. The opening 33 ispreferably counterbored from the bottom of the flange to receive theupper end of the screw 5 and the upper portion of the hole 33 is ofreduced diameter sufiicient to receive a screw driver, or otherimplement, for operating the screw 5. The screw 5 is arranged to coactwith the upper surface of the insulating block l9 adjacent the outeredge thereof whereby, when the screw 5 is threaded downwardly, the lowerend of the screw engages the block l9 and forces the contacts I! fromengagement with the contacts 6, I. The screw 5 is of such dimension andso arranged that when threaded downwardly a sufficient distance to movethe upper end of the screw out of the hole 33, the contacts have beenentirely separated. The cover 2 may be now unscrewed from the housing,and during the removal of the cover, the circuit through the fusereceptacle is open. Accordingly, when the blown out fuse is removed anda new fuse inserted, no arcing will take place, and thus the possibilityof igniting inflammable gases is eliminated, after the cover 2 has beenreplaced and threaded on with the opening 33 arranged in alinement withthe screw 5. The screw 5 is threaded upwardly into the flange of thecover 2, until the contacts I! are permitted to engage with the contacts6, 7. The lower end of the screw may be provided with a small cotter pinor other means to prevent unintentional displacement of the screw fromthe housing.

In Figure 7, 8 and 9, the housing I is provided with a radiallyextending flange 4B which forms a marginal edge surrounding the openingin the top of the box. The cover 4! is provided with a flange 42complemental with the flange 40, and the abutting surfaces of theflanges 4B, 42, are provided with means for baffling ignited or explodedgases within the housing. As here shown, the flange 45 is provided witha plurality of radially spaced apart ribs 43 and the cover withcomplemental circumferential grooves 44. Also, the cover is providedwith a depending annular flange 65 closely fitting the wall of theopening in the housing.

The cover 4! is provided with an inwardly ex tending boss 45 in which ismounted the switch actuating mechanism. The boss 45 is bored or recessedfor a substantial depth to slidably receive the collar 16 of plunger 41,the inner end of which is slidably mounted in an aperture formed in theinner end of the boss 45 and arranged coaxial with the bore of the boss.A helical compression spring 13 encircles the plunger 4'! and coactsagainst the collar 45 to urge the plunger outwardly until the collar 45coacts with disk 39 threaded into the outer end of the bore of the boss45.

The cover M is secured to the housing as by cap screws 5!) and the sidewall of the housing is preferably provided with a thickened portion 51arranged in alinement with the boss 45 on the cover when the cover issecured in place on the housing. The thickened portion 51 is threaded toreceive a screw 52 which is arranged coaxial with the plunger ll andcontacts the outer end of the same when the screw is threaded inwardly,causing the plunger to move inwardly against the action of spring 48with the inner end of the plunger 4'! extending through the boss 45. Ashere shown, a receptacle 53 is mounted within the housing on a suitablesupport 55 and is provided with contacts 55 arranged below thesupporting plate 54. A pair of contacts 56, complemental to the contacts55, are also arranged below the supporting plate 54 and are providedwith screw terminals 56 to which the line is connected. The contacts 55,56, are resilient and the contacts 56 assume an outward position, asshown in Figures 9 and 10. That is, they are normally disengaged, orspaced apart from the contacts 55. The respective pairs of contacts 55,56, are bridged by insulating plates GT, and the plates 5?, associatedwith the contacts 55, are provided with an outwardly extending stem 58which projects through an elongated slot in the plates associated withcontacts 56, and the stem 58 is arranged concentrically with an opening59 in the bracket 60 which supports the plate 54 and receptacle 53. Thestem 58 and the aperture 55 are also arranged concentrically with theplunger 41, and the inner end of the plunger 41 is provided with arecess 5! whereby the inner end of the plunger 4? is Y permitted to besleeved over the stem 58 and to contact the plate 6i of the contacts 55.

In operation, the screw 52 is threaded outwardly through the housing tothe position shown in Figure 9. The cover ll is then placed upon thehousing and secured thereto by means of cap screws 5!] and with the boss45 in alinement with the screw 52 and the contacts 55, 5B. The plunger41 is now pressed outwardly by the spring 48, as illustrated in Figure9. After the cover 4! is thus secured in place, the screw 52 may bethreaded inwardly contacting the outer end of the plunger 4? and causingthe plunger 41 to move inwardly, the inner end of the plunger passingover the stem 58 coacting with contacts 56 and springing them inwardlyinto engagement with contacts 55, thus completing the circuit to thereceptacle 53. With the parts in this position, it is impossible toremove the cover M from the housing, due to the fact that the inner endof screw 52 extends through the collar 49 in the bore of the recess ofboss 45 on the cover, and also the inner end of plunger ll extendsthrough the aperture in bracket 50 which is secured to the base of thehousing. Preferably, there is but slight clearance between the screws 52and the aperture and collar 49, and also a slight clearance between theinner end of the plunger and the aperture in bracket 65, with the resultthat even though the cap screws 55! are loosened, the baiile jointbetween the flange 45 of the housing and 42 of the cover is not renderedinoperable because of the ridges 43 and grooves 44.

The cover M can not be removed from the housing until the screw 52 isthreaded outwardly and the parts, including the contacts 55, 56, are soarranged relatively that the contacts are separated prior to the timethat the screw 52 and plunger 41 are moved outwardly from disengagementwith their associated parts.

The purpose of the stem 58 on contacts 55, and the formation of theinner end of the plunger 47, is to prevent a person unfamiliar with thedevice from accidentally closing the contacts 55, 55, while the cover isremoved from the housing. If it is attempted to insert a tool orimplement through the aperture 59 in bracket 60, contact will be madewith the outer end of the stem 58, causing the inner contacts 55 to bemoved away from the contact 55. In order to close the contacts, it wouldbe necessary to have an implement provided with a recess similar to theinner end of plunger 4i, and such an implement would presumably be onlypossessed by a person familiar with the device and the circuit in whichit was connected, and the closing of the contacts would then beintentional rather than accidental.

It will be observed that the structure of my invention is economical inmanufacture, highly eificient in operation, and particularly welladapted to small explosionproof housings in which are mounted switchingdevices that are not normally manually actuated from the outside of thehousing. Such, for example, as a fuse, as illustrated in theaccompanying drawings.

What I claim is:

1. The combination of an enclosed explosion resisting housing providedwith an opening, a cover for said opening detachably secured to thehousing in flame tight relation therewith, an electrical switch mountedwithin the housing, means carried by the cover and being operable toopen and close the contacts of said switch, and means carried by thehousing and operable from the outside thereof for operating said meanscarried by the cover and to prevent inoperativeness of the flame tightjoint between the cover and the housing while said contacts are closed.

2. The combination of an enclosed explosion resisting housing formedwith an opening in one side thereof, a cover for said opening detachablysecured to the housing in flame tight relation thereto, a switch mountedwithin the housing, means carried by the cover and operable to close thecontacts of said switch, and a member threaded in said housing andoperable from the outside thereof to operate said means carried by thecover to close the contacts of the switch and to prevent inoperativenessof the flame tight joint between the cover and the housing while saidcontacts are closed.

3. The combination of an enclosed explosion resisting housing forelectrical switches being provided with an internally threaded openingin one side thereof, a switch mounted in said housing, a cover memberthreading into said opening, a screw threading into the wall of saidhousing adjacent said opening and being operable from the outside of thehousing to close the contacts of said switch and engage the cover andprevent rotation of the same relative to the housing while said contactsare closed.

4. The combination of an explosion resisting housing for electricalapparatus, said housing being provided with an internally threadedopening in one side thereof to permit installation and removal of saidapparatus, an electrical switch mounted in said housing, a cover forsaid opening provided with threads complemental to those in the housingand being provided with a radially extending flange overlapping themargin of said housing about said opening, a screw threaded through thehousing adjacent said opening and being operable from the outside of thehousing to engage the flange of said cover to prevent removal of thecover from the housing and to effect closing of the contacts of saidswitch.

5. An explosion resisting housing for electrical apparatus provided withan opening to permit installation and removal of said apparatus, anelectrical switch mounted in said housing in flame tight relationtherewith, a cover for said opening detachably secured to said housing,a screw member threaded in the wall of said housing and being cooperablewith the contacts of said switch and said cover to eiTect closing ofsaid contacts and to prevent inoperativeness of the flame tight jointbetween the cover and the housing while said contacts are closed.

6. An enclosed explosion resisting housing for electrical switchesprovided with an opening to permit installation and removal of saidswitch, a cover for said opening detachably secured in flame tightrelation to said housing, a plunger carried by said cover and arrangedin juxtaposition to the contacts of said switch, and means operable fromthe outside of the housing to lock the cover against removal from thehousing and to move said plunger into engagement with said contacts toeiTect closing of the same.

7. An enclosed explosion resisting housing for electrical switches, saidhousing being formed with an opening and having a marginal flangesurrounding said opening, a cover for said opening detachably secured tothe housing and having a flange overlapping said marginal flange of thehousing, and said flanges being provided with coacting means effecting aflame tight joint between the cover and the housing, a switch mounted inthe housing, means carried by the cover and operable to effect closingof the contacts of the switch, and a member threaded through the sidewall of the housing and arranged to engage said switch actuating meansand to operate the same to close the contacts of the switch and toprevent inoperativeness of the flame tight joint between the cover andhousing while said contacts are closed.

8. An enclosed explosion resisting housing for electrical switches, saidhousing being provided with an opening to permit installation andremoval of a switch, a switch mounted in the housing, a cover for theopening detachably secured to the housing and provided with an inwardlyextending portion, a plunger slidably mounted in said portion andarranged when moved inwardly to close the contacts of said switch, amember threaded through the side wall of the housing and arranged toengage said plunger and move the same inwardly when the cover is securedto the housing and to lock the cover against removal While said plungeris in its inner position.

9. The combination of an enclosed explosion resisting housing, anelectrical switch mounted therein, said housing being formed with anopening in one side to permit installation and removal of the switch, acover detachably secured to the housing in a flame tight relationtherewith and forming a closure for said opening, a member screwthreaded in the side wall of the housing adjacent the marginal edge ofsaid cover and being operable from the outside of the housing to effectclosure of the switch contacts and to prevent inoperativeness of theflame tight joint between the cover and the housing while said switchcontacts are closed.

RAYMOND H. OLLEY.

' CERTIFICATE OF CORRECTION. Patent no. 2,156,572. May 2, 19 9.

RAYMOND H OLLEY. It is hereby certified that error appears in theprinted specification of the above numbered patent requiring correctionas follows; Page 5, first column, line .66, and second column, line l,'claim 5; strike out the words "in flame tight relation therewith" andinsert the same after "housing" and before the comma, second column,line 2, same claim; and that the said Letters Patent should be read withthis correction therein that the same may conform to the record of thecase in the'Petent Office. I Y Signed nd" sealed this 27th day of June,A. D. 19 9.

Henry Van Arsdale (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION. Patent No. 2,155,572. I May 2', 1959.

, I RAYMOND H OLLEY. It is hereby certified that error appears in theprinted specification of theabove numberedpatent reqniring correction asfollows Page 5, first column, line .66, and second column,11116131111111 5, strike out thewords "in flame tight relationtherewith" and insert the same after, "housing" and before the comma,second column, line 2, same claimyand that the said Letters Patentshould be read with this correction therein that the same may conform tothe record of the case in thePatent Office. I 7 Signed and sealed this27th day of June, A. D. 1959.

Henry Van Arsdale (Seal) Acting Commissioner of Patents.

